Trapeze profile for 3D letters, lines
I made a textobject in Blender, but with svg curves this could also work. The bevel is the outer form of your geometry. Than I added a curvecircle and defined it right as bavel object (yellow) and got the result at the right sight. You should set the vektor handles (v in curve edit mode) of the circle to free to get sharp angles. Also you should use only one core as a contour. (Red in the exmaple)